class_docstr: A class that handles the parameters of Tensor Tracer.
docstr: Checks if the given submode is valid.
docstr_tok: ["Checks","if","the","given","submode","is","valid","."]
code: def _get_submode(self):
      """Checks if the given submode is valid."""
  
      found, submode = self.get_flag_value(FLAG_NAME_SUBMODE)
      if not found or not submode:
          submode = _SUBMODE_DETAILED
      if not submode:
          return
      valid_submodes = [_SUBMODE_DETAILED, _SUBMODE_BRIEF]
      if submode not in valid_submodes:
          raise ValueError(
              'Invalid submode "%s" given to the Tensor_Tracer.'
              "Valid submodes are: %s" % (submode, valid_submodes)
          )
      return submode
  
imports: import os
  import os.path
  import re
  from absl import flags
  from tensorflow.python.ops import linalg_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 8 for calling the TTParameters obj's underlying member method code with example usage: obj._get_submode() and returns: submode